Trends and Disparities of Chronic Lymphocytic Leukemia Mortality in the United States from 1999 to 2020

Background

Chronic lymphocytic leukemia (CLL) is the most common chronic leukemia in the United States (US). In the last decade, the treatment landscape of CLL has significantly evolved, and the clinical outcomes improved. However, data on the mortality trends of CLL is not well-established.

Objective

This study aimed to analyze the trends in mortality rates due to CLL and to assess the disparities in the mortality rates among different sex, ages, races, and geographic locations.

Methods

We obtained death certificate data for CLL mortality among patients aged 35 years and above from the Centers for Disease Control and Prevention's Wide‐Ranging Online Data for Epidemiologic Research (CDC WONDER) database. CLL (International Classification of Diseases, Tenth Revision [ICD-10] C91.1) was listed as the underlying cause of death. Age-adjusted mortality rates (AAMRs) per 100,000 individuals were calculated, and the trends over time were analyzed by measuring the average annual percent change (AAPC) using the Joinpoint Regression Program. Subgroup analyses were conducted by sex, race, age, census region, and urbanization level.

Results

In the 22-year study period from 1999 to 2020, 97,186 deaths attributed to CLL were reported in the US. The CLL mortality rate decreased from 3.23 (95% CI, 3.13 - 3.32) per 100,000 individuals in 1999 to 2.05 (95% CI, 1.99 - 2.11) per 100,000 individuals in 2020 with the AAPC of -2.09 (95% CI, -2.69, -1.49). The highest AAMR was observed among non-Hispanic White men (4.14 [95% CI, 4.10 - 4.17] per 100,000 individuals), followed by non-Hispanic Black men (3.48 [95% CI, 3.37 - 3.59] per 100,000 individuals), non-Hispanic White women (1.88 [95% CI, 1.86 - 1.90] per 100,000 individuals), and non-Hispanic Black women (1.61 [95% CI, 1.55 - 1.67] per 100,000 individuals). Figure 1 shows the trends of AAMR in non-Hispanic White and non-Hispanic Black men and women over the years. Black individuals had the greatest decline in AAMR over the years with the AAPC of -2.87 (95% CI, -3.31, -2.42) whereas Hispanic individuals had the smallest decline in AAMR over the years with the AAPC of -1.50 (95% CI, -2.30, -0.69). Patients aged 75-84 years had the highest AAMR at 0.99 (95% CI, 0.98 - 1.00) per 100,000 individuals among different age groups. The greatest decline in AAMR was reported among patients aged between 45-54 years with the AAPC of -4.91 (95% CI, -6.16, -3.65). Those who lived in the Midwest region had the highest AAMR (2.93 [95% CI, 2.89 - 2.97] per 100,000 individuals), followed by the Northeast region (2.52 [95% CI, 2.49 - 2.56] per 100,000 individuals), the South region (2.48 [95% CI, 2.46 - 2.51] per 100,000 individuals), and the West region (2.38 [95% CI, 2.34 - 2.41] per 100,000 individuals). The greatest decline in AAMR over the years was observed among those who lived in the South region with the AAPC of -2.42 (95% CI, -2.68, -2.16). A higher AAMR was observed in the rural population (2.87 [95% CI, 2.83 - 2.91] per 100,000 individuals) in comparison to the urban population (2.53 [95% CI, 2.51 - 2.55] per 100,000 individuals).

Conclusion

CLL mortality has declined over the last two decades, likely due to the introduction of novel therapies. However, disparities among different sex, races, ages, geographic regions, and urbanization levels still exist. Our study underscores the importance of addressing these disparities and improving outcomes for susceptible individuals affected by CLL.